Purification and Characterization of Caprine Ghrelin and Its Effect on Growth Hormone Release
Purification and Characterization of Caprine Ghrelin and Its Effect on Growth Hormone Release
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DOI：
10.1007/s12031-010-9379-0
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发表时间：
2010-09-01
影响因子：
3.1
通讯作者：
Kojima, Masayasu
中科院分区：
文献类型：
--
作者：
Ida, Takanori;Miyazato, Mikiya;Kojima, Masayasu
Ghrelin是生长激素促分泌素受体（GHS-R）1a的内源性配体，是一种在第三个丝氨酸残基（Ser（3））上经正辛酸修饰的新型多肽。Ser（3）的辛酰基修饰对于受体结合或生长激素释放是必需的。在这里，我们报告山羊ghrelin的纯化及其在山羊中的生理作用。山羊生长素释放肽的主要形式是一种27个氨基酸的肽，其在Ser（3）处被辛酰化（C8：0）并且缺乏Gln（14），Gln存在于大鼠和人生长素释放肽中。此外，我们确定了山羊生长激素释放肽中的各种酰基修饰：壬酸（C9：0）、癸酸（10：0）、不饱和辛酸（C8：1）和未鉴定的脂肪酸修饰。我们观察到酰基修饰的差异影响GHS-R1 a的活化。此外，合成牛生长激素释放肽的管理增加山羊血浆生长激素（GH）水平。因此，本研究表明山羊生长激素释放肽的结构分歧，并表明生长激素释放肽参与反刍动物的生长激素释放。
Ghrelin, a novel peptide modified by n-octanoic acid at the third serine residue (Ser(3)), serves as an endogenous ligand for the growth hormone secretagogue receptor (GHS-R) 1a. The octanoyl modification at Ser(3) is essential for receptor binding or growth hormone release. Here, we report the purification of caprine ghrelin and its physiological role in goats. The major form of caprine ghrelin is a 27 amino acid peptide that is octanoylated (C8:0) at Ser(3) and lacks Gln(14), which is present in rat and human ghrelin. Additionally, we identified various acyl modifications in caprine ghrelin: nonanoic (C9:0), decanoic (10:0), unsaturated octanoic acids (C8:1), and an unidentified fatty acid modification. We observed that differences in acyl modifications affected GHS-R1a activation. In addition, administration of synthetic bovine ghrelin increased plasma growth hormone (GH) levels in goats. Thus, the present study indicates a structural divergence in caprine ghrelin and suggests that ghrelin is involved in GH release in ruminants.